Gear drive for record players with preferably more than three different speeds



Dec. 16, 1958 S. GEAR DRIVE FOR RECO MORE THAN THREE D Filed ZAORALEK 2,8 ERS WITH PREFERABLY IFFERENT SPEEDS RD PLAY July 18, 1955 United States Patent Orifice 2,864,261 Patented Dec. 16, 1958 GEAR DRIVE FOR RECORD PLAYERS WITH PREFERABLY MORE THAN THREE DIFFER- ENT SPEEDS Application July 18, 1955, Serial No. 522,786 Claims priority, application Germany July 28, 1954 3 Claims. (Cl. 74190) The present invention relates to the construction of a gear drive for record players with preferably more than three different speeds. Up to the present, standardspeed record players were machines having 78, 45 and 33 revolutions per minute. In this case it is possible to record and reproduce sound and speech within the range of 40 up 14,000 cycles per second.

It has, however, already been proposed to once more reduce the speed by one half, i. e. to about 16 revolutions per minute. With the customary disc-record size means that a medium-length novel can be reproduced in two to three hours with three disc records playable on both sides. Possibility of reproduction is, however, confined to speech. It can no more be considered to reproduce music at these low speeds.

Such changes of speed naturally have their effect on the gear drive of the machine for which the constructions that have been customary up to the present, no more suffice.

The gear drive according to the invention, for record players having preferably more than three different speeds is characterized by the fact that a stepped pulley is provided in the gear between the motor and the disc tray, to which pulley an intermediary pulley can be set that can be shifted parallel to the axis of the stepped pulley as well as radially to it by means of a hand-operated speed-setting device. This is appropriately'done in such a manner that a guide bush of the intermediary pulley is flexibly carried in the slit of a guide rod that can be adjusted parallel to the axis of the stepped pulley, whereas a second guide rod lies in at least one direction against the guide bush of the intermediary pulley, this second guide rod being adjustable parallel in one direction relative to the first guide rod and participating in the adjusting movement of the first guide rod, in such a manner that its adjusting movement effects an adjustment of the intermediary pulley in radial direction of the stepped pulley. To this end, the first guide rod can be firmly secured to a base element that is arranged on a steepthread spindle which can be turned by means of the speed-setting device, whereas the second guide rod that acts on the guide bush of the intermediary pulley carries the base element in a slit, the position of the second guide rod relative to the first one being determined by a follower arranged in such a way that it can be shifted parallel to the axis of the stepped pulley. Said follower is carried by an adjusting element, preferably fork-shaped, against which lies a cam plate which is arranged on the threaded spindle.

The drawing shows by way of example a form of construction of the invention.

Fig. 1 is a longitudinal cross-section of the record player through the line II of Fig. 2;

Fig. 2 is a plan View of the record player with.the disc tray removed;

Fig. 3 shows a vertical cross section of the record player through the line III-III of Fig. 2, whereas Fig. 4 corresponds to a partial section through the line IV-IV of Fig. 2.

In all diagrams 1 designates the base plate of the machine carrying at 2 the socket for the tone arm 3 and at 4 the speed-setting device. 5 designates the drive motor. The shaft of its rotor carries the stepped pulley 6 against which can be placed flexibly an intermediary pulley 7 unthe action of spring 8. Shaft 9 of the intermediary pulley 7 is carried in guide bushing 10 that can be shifted in the slit 11 of the guide rod 12. Guide rod 12 is secured to a base element 13 which is arranged on the steep-thread Worm gear 14. Worm gear 14 is carried on the trunnion 15 that in its turn is carried by and can be turned in the bearing lug 16 of the lower base plate 17. At 18 a toothed wheel is fixed on the trunnion 15 with which toothed wheel a toothed rack meshes as can be seen in Fig. 2 at 19. Besides, trunnion 15 carries a camplate 20 which is arranged in the adjusting element 22 that is fork-shaped at 21. The adjusting element 22 holds the guide bolt 23 which is adjustable in height, bolt 23 carrying the guide rod 24. In a slit 25 .of guide rod 24- is arranged the base element 13. At its free end where the traction spring 8 engages, guide rod 24 envelops the guide bush 10 of the intermediary pulley 7 the circumference of which is clad with the friction covering 26. The toothed rack 19 meshes-as shown in Fig. l with the toothed wheel 27 that is arranged on the hollow shaft 28 of the speed setting device. Fixed on the hollow shaft 28 is the selector dial 29 which carries cup-like recesses 30 destined for engaging the tips of the fingers. The tops of the recesses 30 for engaging the finger tips can consist of transparent material so that an incandescent bulb arranged below the selector dial may light up the transparent material. The bottom of these cup-like recesse carries numbers indicating the respective number of revolutions per minute. A finger stop 31 secures the speed setting device and the parts of the gear attached to it always having the position corresponding to the speed that has been set. In the present case Fig. 2 shows the setting of the speed setting device to the value zero, i. e. that the gear is stopped. Accordingly the intermediary pulley 7as can be seen in Fig. l-is completely lifted off taper pulley 6.

Intermediary pulley 7 with friction covering '26 transmits its motion onto the friction wheel 32. Friction Wheel 32 is pivotably carried on the guide lever 33. Guide lever 33 has its pivot at 34. Friction wheel 32 carries a rubber head 35. Rubber bead 35 engages the inside of flange 36 of the rotary disc tray 37. At 38 there is provided a supporting ring for the rotary tray. The tray shaft 39 cast into the supporting ring 38 is supported in two bearing bushes 40, 41 and is carried by the ball 42.

The hollow shaft 28 of the selector dial also accommodates an inner tube 43 which leads tothe potentiometer 44. On the top, inner tube 43 opens out into the rotary knob 45, it being possible to adjust the potentiometer by means of the rotary knob.

A capacitor that is not shown in the drawing is arranged with the potentiometer in order to suppress the needle noises of the pickup 46 within given limits. On the hollow shaft 28 there is also provided grooved ring 47 in connection with a blade spring engaging in its grooves, in order to facilitate engaging of the selector dial 29 in the desired positions for setting the transmission ratio.

Control shaft 48 carries the tone arm 3 and is connected with control cam 49. The contact levers 50 and 51 are arranged at both sides ofc-ontrol cam 49 in order to come under the action of control cam 49 in accordance with the direction of deflection of the tone arm, so that mot-or 5 is cut in or out automatically.

At 52 a device is provided for making possible unhindered connection of different main voltages.

The guide bushings 53 serve for an entirely concentric guiding of taper pulley 6; they are shown in detail in Fig.4.

The mode of operation of stood from the foregoing.

When operating selector dial 29, the speed setting motion is transmitted through the hollow shaft 28 onto the toothed wheel 27. This imparts a corresponding setting motion to toothed rack 19. This setting motion is transmitted to toothed wheel 18 of the threaded bolt 15, 14. The threaded bolt is turned in conformity so that the base element 13 screws itself upwards on the threaded spindle 14. This also moves the guide rod 12 upwards so that the intermediary pulley '7 is correspondingly adjusted in height. Intermediary pulley 7 thus comes into the positional level of the step of stepped pulley 6 which corresponds to the desired transmission ratio. Simultaneously with the turning of threaded bolt 14, 15 a rotation of the cam disc has been carried out, which rotation has resulted in a corresponding shifting of adjusting element 22. This motion was followed by guide bolt 23 which previously already had followed the adjustment in height of guide rod 12. Thus the guide bush 10 of the intermediary pulley 7 was adjusted through the guide rod 24 in such a manner that the intermediary pulley 7, in spite of the changed diameter of the step against which the intermediary pulley now lies, can adjust itself correspondingly thus insuring positive action of the friction engagement. As far as change over is effected to steps of smaller diameter of the stepped pulley 6, spring 8 provides the necessary contact pressure, whereas in the opposite direction adjustment is reached against the action of spring 8 through the parts 20, 22 and 24.

I claim:

1. Gear drive for a record players with more than three different speeds for the disc tray comprising in combination: a drive motor, a stepped pulley disposed on the shaft of said drive motor, a disc tray, a friction wheel engaging the periphery of said disc tray for driving said disc tray, an intermediary pulley adapted to transmit its rotating motion on to said friction wheel, said the gear is directly underintermediate pulley arranged to rotate on an axle, a guide L bushing receiving said axle, a hand operated adjusting device for the adjustment of the speed of the disc tray, means in said adjusting device adapted to adjust the intermediary pulley as a function of the actuation of the speed adjusting device in the direction of the axis of rotation of the stepped pulley and also vertically to this axis so that the intermediary pulley either contacts one of the steps of the stepped pulley or is completely lifted up from said stepped pulley, said means comprised of two guide rods, the first of said guide rods adjustable as a function of the actuation of the speed adjusting device so as to be adjusted in parallel to the axis of the stepped pulley and contacting the guide bushing of the intermediary pulley, said contacting adapted to displace the intermediary pulley in the same direction, the second guide rod adjustable as a function of actuations of the speed adjusting device so as to be adjustable simultaneously with the first guide rod in a direction which is perpendicular to the axis of the stepped pulley and contacting the guide bushing, said contacting adapted to give the intermediary pulley different radial distances from the axis of the stepped pulley.

2. Gear drive according to claim 1 in which the first of said guide rods is rigidly connected with the one of two parts which are connected through worm and wormgear, while the other of the two parts can be turned under the influence of the speed adjusting device, said first guide rod comprising a slot adapted to receive the guide bushing of the intermediary pulley, a cam plate disposed at that of the two parts connected through worm and worm-gear which can be turned under the influence of the speed adjusting device, means in contact with the cam plate which are adapted to transmit their position which is variable due to the shape of the rim of the cam plate on to said second guide rod, said second guide rod having a recess, said recess adapted to receive the guide bushing of said intermediary pulley.

3. Gear drive according to claim 2 in which the first of said guide rods rigidly connected with the form bushing of a worm gear having a steep threaded worm spindle which can be turned and on which a gear wheel is disposed, said gear drive further comprising a racl: engaging said gear wheel, said rack being capable to be displaced into different positions under the influence of the speed adjusting device, said first guide rod comprising a slot adapted to receive the guide bushing of the intermediary pulley, a cam plate arranged at said worm spindle, means in contact with the cam plate which are adapted to transmit their position which is variable due to the shape of the rim of the cam plate on to said second guide rod, said means comprised of an adjusting ele' ment enveloping the cam plate in fork-shaped manner, a guide pin movable in the direction of the axis of the stepped pulley rigidly connected with the adjusting element and the second guide rod, said second guide rod having a recess, said recess adapted to receive the guide bushing of said intermediary pulley.

References Cited in the file of this patent 4 UNITED STATES PATENTS 2,260,289 

